I thought the 1 of the 6 Hidden City Challenges was glitched too because when I paused the game and L2 (PS4) to check status of my challenges, only 5 Hidden City challenges comes up. In my case it was the Dunkin' Bones challenge was missing and I realized the reason the challenge wasn't listed on the challenges list is because I hadn't even taken out 1 of the 3 Dunkin' Bones. Once I learned where they were, I proceeded to the first one and once I was credited for taking it out, then Dunkin' Bones appeared on my challenge list at 33%. From there I took out the second Dunkin' Bones and shortly after that, the third and final one, completing all challenges and receiving 100% World Map.
So the reason I couldn't find the circled star for this challenge in the first place is because you have to know the challenge exists and take out one of however many required (3 in this case) for the percentage count to even start. Had I not Googled all 6 challenges and used "process of elimination" to determine which challenge I lacked, I'd still be high diving or collecting condor feathers, thinking one of those challenges was short one.